Tach problem

[FVBonura]

UPDATE

Thank you Everyone in this thread.

I replaced ignition control module, packing it with fresh conductive grease, and the car went from firing on 6 to 7 plugs. This one replacement also fixed the tachometer problem and the check engine light. AGAIN THANK YOU!!!

I then swapped out the rear coil pack. I noted the dead terminal was also the hottest, being I just drove the car. The heat burned my hand it was so hot and I have thus concluded manifold heat was the problem. The coil pack died of an overdose of heat.

While the rear pack was out, I took some aluminum sheet metal about 5" x 5" and fabricated a heat shield that mounts on the DIS bracket not the manifold bolts. The new shield was polished to a mirror-finish so it should work nicely as a heat shield. I bent the aluminum on a 4" diameter pipe to form a smooth 90 degree curve. The shield now fits perfectly over the manifold by cylinder #1 and leaves about 1/4" clearance around everything.

The car now fires on all 8 plugs, the idle is perfect, the tachometer is perfect, the car is faster, and I'll wager my gas mileage is better too. After taking her up to speed and getting her good and hot, on my test run, I checked the shield and it was hot but I did not burn my hand and the rear coil pack was very warm but only a fraction of the temperature it was on the old damaged unit.

I hereby declare the project a complete success and I must declare the membership of this forum a group of genuine gentlemen and scholars.

Again to all of you, THANK YOU VERY MUCH!!! Be well in all your endeavors.

Delray Dude I will look into finding a 93-94 Ranger header. That header idea sounds absolutely inspired. I may very well weld a coupling on it for the EGR tube anyway because Pennsylvania laws are a bit touchy with visual emissions inspections. The EGR does not necessarily have to work but it best look like it does here in PA.

Once again you guys are mountain of help.

 

[Delray Dude]

Delray Dude I will look into finding a 93-94 Ranger header. That header idea sounds absolutely inspired. I may very well weld a coupling on it for the EGR tube anyway because Pennsylvania laws are a bit touchy with visual emissions inspections. The EGR does not necessarily have to work but it best look like it does here in PA.

Once again you guys are mountain of help.

Glad to hear your problem is solved.

Neat idea for the heat shield - I might have to fabricate one myself.


A hint: Since you have to have the "appearance" - I know that the EGR bung on the Ranger headers where the pipe screws onto it you can put a dime on the end of it (maybe even a penny) and tighten down the tube - it can't be seen (the nut and pipe cover it) and blocks the EGR but gives the illusion of it being stock. I would have done this to mine, but we don't have emissions down here in Florida, so i just cut the pipes off and sealed them.

I just installed a 140 MPH speedo and man it looks much better than the 85 MPH.

 

[bonestock87]

FWIW I believe we all have been through the same problem as the OP. I'll step up and be a witness to the fact that ICM's can test ok at the store but still be bad. And Rock Auto has them for $89 last I checked.

 

[Delray Dude]

FWIW I believe we all have been through the same problem as the OP. I'll step up and be a witness to the fact that ICM's can test ok at the store but still be bad. And Rock Auto has them for $89 last I checked.

Yep. I agree - I acquire them every time i run accross one in the junk yard - i carry a spare in the car - just in case - i usually get one off a newer ranger with little miles - i do plug them in and check them to make sure they are good on my car. Last week my neighbor has a 94 Ranger and was having problems - he couldn't figure it out. I tossed him one of mine, he put it in - and viola...truck runs like it should. He was happy - gave me 20 bucks and a case of beer.

 

[bonestock87]

He was happy - gave me 20 bucks and a case of beer.

Win!

 

[FVBonura]

Heat Shield

The heat soaking problem on the rear coil pack, for those who have a stock exhaust manifold, seems to be a serious enough problem so I decided to post the images of how I solved the problem. If I spare one of my brothers from suffering coil failure, it's worth it. Some of the high performance coil packs are downright expensive and a cheap piece of aluminum is great insurance even on a cooler-running header set up so it cant do any damage to the ignition system. I went outside and took some pics, have a look...

This is the shield from the rear. Note how it gently curves around the manifold but does not touch it. This allows some air to pass between the shield and the manifold and works wonders reducing the temperatures of everything above it.

This photo is a little closer, I took off the air intake tube off to get a better view, note the bent tab on top and how it is bolted to the DIS bracket and the side of the cylinder head. I cut the tab and cut out a slotted hole for the bolt. I bent the tab 90 degrees on a vice. Very simple stuff, no special tools required.

Front view of the shield.

Side view looking at the cylinder head. Note how the shield uses the existing DIS bracket bolt. This bolt, located an inch away from the manifold, is a much cooler attachment point and transfers far less heat from the engine allowing the shield to cool in the passing air and preventing most of the heat from the manifold from reaching the coil pack above.

 

[Delray Dude]

Side view looking at the cylinder head. Note how the shield uses the existing DIS bracket bolt. This bolt, located an inch away from the manifold, is a much cooler attachment point and transfers far less heat from the engine allowing the shield to cool in the passing air and preventing most of the heat from the manifold from reaching the coil pack above.

Looks good. great idea

 

[92turbostang]

icm

Thank you guys this helped me out too. The dual coil pack doesn't change how the motor runs at all. So the second coil pack is mostly for emissions purposes only correct?

 

[Delray Dude]

Thank you guys this helped me out too. The dual coil pack doesn't change how the motor runs at all. So the second coil pack is mostly for emissions purposes only correct?

mostly so - IIRC they fire one pack just before the 2nd one (like .25 seconds) and was designed to help on emissions and help some (very little) in the horsepower department. But if you have one pack that is dead - and the other is fine - it'll run fine and you won't know the difference....well until the other pack start's it's death!


I just check mine every 6 months or so to see if they are firing by unplugging one and see if the engine fires on all 4 just to know for sure then unplug the other one.